Patient information

If you are taking a privately prescribed weight loss injection and are using contraception or HRT, it is essential that you are aware that GLP-1 agonists lower the effectiveness of oral contraceptive pills and the oral progesterone element of HRT.

More information here:

Faculty of sexual and reproductive healthcare

Primary care womens health society

Guidance

Contraception

The current faculty of sexual and reproductive health guidance is that a highly effective contraception choice should be used during and after treatment with a GLP-1 agonist.

These options are:

• Male or female sterilisation
• IUD or IUS (coils)
• Progesterone containing implant

Tirzepatide (Mounjaro) has been shown to reduce the effectiveness of oral contraceptive pills.  Current guidance is to use an additional barrier contraception (e.g. condoms) for the first 4 weeks after starting the medication AND 4 weeks after any increase, or alternatively switching to a non-oral contraception whilst using this medication.

Please request a routine GP appointment or attend the family planning clinic to discuss contraception further if required.

HRT – Hormone replacement therapy

Non-oral progesterone (patch or US) is preferred while using a GLP-1 agonist.

If oral progesterone is used, higher doses should be used for 4 weeks after starting medication AND 4 weeks after any dose increases.

If you need to discuss your HRT regime, please request a routine appointment with our in house clinical pharmacist team.